KR100901231B1 - Biometrics authentication apparatus - Google Patents

Abstract

In the biometric authentication device, the storage unit stores a dictionary containing biometric information of a registered person. The information acquiring means acquires biometric information of the subject. The authentication means authenticates the validity of the subject on the basis of an index value indicating the similarity between the biometric information previously stored by the storage means and the biometric information acquired by the information acquisition means. The first management means updates the dictionary of the storage means based on the biometric information acquired by the information acquiring means in the first case where the indicator value indicates a similarity higher than the first threshold value, and the indicator value is lower than the first threshold value. In the second case showing a similarity higher than the second threshold value set lower than the first threshold value, a new dictionary according to the biometric information acquired by the information acquiring means is generated and stored in the storage means.

Biometric information, threshold, storage device, dictionary, information acquisition unit, authentication unit

Description

Machine-readable medium containing a biometric authentication device, biometric authentication method and program instructions {BIOMETRICS AUTHENTICATION APPARATUS}

TECHNICAL FIELD This invention relates to the technique of authentication using biological feature amounts (hereinafter, referred to as "biological information") such as fingerprints and fingerprints.

Biometric authentication which judges the validity of the subject by matching the collection of biometric information (hereinafter referred to as "the dictionary") previously collected from the registered legitimate user and the biometric information collected from the subject of authentication (hereinafter referred to as the "subject"). The technique of (biometrics authentication) has been proposed conventionally. In Patent Document 1, in order to maintain the accuracy of authentication even when the biometric information of a legitimate user changes, the similarity between the biometric information collected from the subject and the previous biometric information exceeds the threshold (that is, the subject is justified). In the case of a user), the structure which updates a dictionary suitably is disclosed.

[Patent Document 1] Japanese Patent Application Laid-Open No. 11-184491

However, even in a configuration in which the dictionary is updated from time to time as in Patent Document 1, the authentication accuracy is maintained at a high level in the case where the biometric information varies greatly in a short time depending on the physical condition of the legitimate user and the surrounding environment at the time of authentication. It is difficult to do For example, biometric information (e.g. cepstrum) collected from human voices fluctuates greatly between immediate activity and daylight activity. In addition, in a static environment and a noisy environment, the method of speech (particularly volume and sound quality) is quite different. Based on the configuration of Patent Literature 1, in which one dictionary is used for authentication, if an attempt is made to properly authenticate a legitimate user in each case having a different time or environment as described above, there is an increased possibility that an unjust subject is mistaken for legitimacy. There is a problem.

In view of such circumstances, the present invention aims to solve the problem of maintaining the accuracy of authentication at a high level even when biometric information fluctuates.

According to a first aspect of the present invention, the above and other objects include: storage means for storing a dictionary containing biometric information of a registered person; Information obtaining means for obtaining biometric information of the subject; Authentication means for authenticating the validity of the subject on the basis of an index value indicating the similarity between the biometric information previously stored by the storage means and the biometric information acquired by the information acquisition means; In the first case where the index value indicates a similarity lower than the first threshold value, the dictionary of the storage means is updated based on the biometric information acquired by the information acquiring means, and the index value is lower than the first threshold value but is higher than the first threshold value. In the second case showing a higher degree of similarity than the second threshold set lower, it is achieved by providing a biometric authentication device including a dictionary management means for generating a new dictionary according to the biometric information acquired by the information acquisition means and storing it in the storage means. Can be.

According to the above aspect, since a new dictionary is created in the second case, it is possible to maintain the accuracy of authentication at a high level even when the biometric information of a legitimate user (ie, a registered person) changes in the short term. Moreover, the structure by which a 1st threshold value and a 2nd threshold value are changed according to operation by an operation part by a user is also employ | adopted.

In a preferred aspect of the present invention, the authentication means affirms the validity of the subject in the first case, and negates the validity of the subject in the case where the indicator value indicates a similarity lower than the second threshold.

In this aspect, since the 1st threshold value and the 2nd threshold value used as a criterion for judging whether the existing dictionary is updated or the addition of a new dictionary are used also as a criterion for judging the validity of the subject, it is different for each judgment. Processing is simplified compared to the configuration in which the threshold is used.

In a preferred aspect of the present invention, the biometric authentication device further comprises auxiliary authentication means for authenticating the validity of the subject separately from the authentication means, wherein the pre-management means, in the second case, wherein the auxiliary authentication means is the validity of the subject. If affirmative is given, a new dictionary is created. If the auxiliary authentication means denies validity of the subject, a new dictionary is not created.

In the above aspect, since a new dictionary is created only when the validity of the subject is judged by the auxiliary authentication means when the biometric information is between the first threshold value and the second threshold value, the subjects other than the legitimate user. Events such as the creation of a new dictionary based on biometric information obtained from the system are effectively excluded.

A biometric authentication device according to one aspect of the present invention includes storage means for storing a plurality of dictionaries each containing biometric information of a registered person, information obtaining means for acquiring biometric information of a subject, and a plurality of dictionaries. Corresponding means for authenticating the validity of the subject on the basis of a plurality of indicator values indicating the similarity between the respective biometric information stored in the storage means and the biometric information acquired by the information acquiring means, respectively; In the first case where the index value at which the similarity degree among the values is the maximum is higher than the first threshold value, the dictionary corresponding to the maximum index value among the plurality of dictionaries in the storage means is based on the biometric information acquired by the information obtaining means. And in a second case, indicating a similarity higher than the second threshold, wherein the maximum indicator value is lower than the first threshold but lower than the first threshold. Creating a new dictionary in accordance with the biometric information acquired by the beneficial means includes a dictionary management means for storing in the storage means.

According to the above aspect, since a new dictionary is created in the second case, similarly to the first aspect, it is possible to maintain the accuracy of authentication at a high level even when the biometric information of a legitimate user changes in the short term.

In the biometric authentication device according to the second aspect, when the total number of dictionaries stored in the storage means reaches a predetermined number, a configuration including a dictionary reduction means for reducing the dictionary is preferably employed.

In the preliminary reduction means configuration, it is possible to reduce the capacity required for the storage means. The maximum value of the total number of dictions can be changed in accordance with an operation on the operation unit by the user.

For example, in the biometric authentication device, the dictionary management means counts the number of updates for each dictionary stored in the storage means when each dictionary is updated by the dictionary management means. Then, the dictionary reduction means reduces the dictionary whose update count counted from the storage means is smaller than the threshold count value.

In the biometric authentication device, the dictionary management means also counts the number of non-updates for each unupdated dictionary stored in the storage means while the other dictionary is updated by the dictionary management means. Then, the dictionary reduction means reduces the dictionary whose non-update count exceeds a threshold from the storage means.

According to the above aspect, since the dictionary with a relatively low frequency of use among the plurality of dictionaries is deleted, the capacity required for the storage means can be reduced while maintaining the accuracy of authentication at a high level. Further, the threshold value compared with the number of updates or the number of non-updates can be changed in accordance with the operation by the user to the operation unit.

Or, the dictionary management means evaluates the similarity between the plurality of dictionaries stored by the storage means. The dictionary reduction means then reduces the two dictionaries whose similarity exceeds the threshold into one dictionary by merging them or deleting one of them.

In this case, since a plurality of dictionaries with high similarity are reduced to one dictionary, the capacity required for the storage means can be reduced without impairing the action of responding to variations in biometric information. The threshold value compared with the similarity degree of each dictionary changes according to the operation to the operation part by a user.

The biometric authentication device according to each of the above aspects is also specified as a method for authenticating a subject. A biometric authentication method according to one aspect of the present invention obtains biometric information of a subject, and is an index value indicating the similarity between the registered person's biometric information contained in a dictionary stored in the storage means and the subject's acquired biometric information. Based on the obtained biometric information, the dictionary of the storage means is updated based on the acquired biometric information, and the indicator value is higher than the first threshold value. In the second case which shows a similarity higher than the second threshold value set lower than the first threshold value, the new dictionary according to the obtained biometric information is generated and stored in the storage means.

According to the above method, the same action and effect as the biometric authentication apparatus of this invention are exhibited.

The biometric authentication device according to the present invention is realized by hardware (electronic circuit) such as a DSP (Digital Signal Processor) dedicated to each process. Alternatively, it may be realized by cooperation between a general-purpose computing device such as a central processing unit (CPU) and a machine-readable medium including a program. That is, the machine-readable medium is provided to store a dictionary containing biometric information of a person registered with the computer. The machine readable medium is used in a computer having a storage means for storing a dictionary containing biometric information, and the machine readable medium includes information acquisition processing for acquiring biometric information of an authenticated person and a dictionary stored in the storage means. Authentication processing for authenticating the validity of the subject based on the index value indicating the similarity between the biometric information and the biometric information acquired by the information acquisition process, and the information acquisition process when the index value indicates the similarity lower than the first threshold value. Obtaining the information in a second case in which the dictionary of the storage means is updated on the basis of the biometric information acquired at and the index value exhibits a similarity higher than the second threshold set lower than the first threshold but lower than the first threshold. The computer is configured to perform a dictionary management process of generating a new dictionary according to the biometric information acquired in the process and storing it in the storage means. Contains program instructions executable by the computer.

Also with the above program, the same action and effect as the biometric authentication apparatus which concerns on this invention are exhibited. In addition, the program of the present invention is provided to the user in a form stored in a portable recording medium such as a CD-ROM and installed in a computer. Or it is provided from the server apparatus in the form of distribution via a network, and is installed in a computer.

<A: Configuration of Biometric Authentication Device>

1 is a block diagram showing the configuration of a biometric authentication device according to an embodiment of the present invention. The biometric authentication device 100 is adapted to determine the validity of the subject (whether or not the subject is a registered regular user) on the basis of the voice when the subject speaks a specific word. It is mounted on various electronic devices such as an information processing device. As shown in FIG. 1, the biometric authentication device 100 includes an information acquisition unit 10, a storage device 20, a control unit 30, an operation unit 40, and an output unit 50.

The information acquisition unit 10 is a means (information acquisition unit) for acquiring the biometric information DIN of the subject, and includes an input unit 12 and an analysis unit 14. The input unit 12 is a device (for example, a microphone) that picks up the voice of the subject. The analyzer 14 analyzes the voice input to the input unit 12 to generate biometric information DIN reflecting the characteristics of the voice. For example, the analyzer 14 generates, as the bioinformation DIN, a time series vector sequence of voice cepstrum spoken by the subject. For this purpose, means for executing various operations including frequency analysis (e.g., Fast Fourier Transform (FFT) processing) is preferably employed as the analysis section 14.

The storage device 20 is a means (memory means) for storing various DICs (DIC_1 to DIC_m) and various variables used for the processing of authentication. Various devices such as a magnetic memory device, a semiconductor memory device and an optical memory device are employed as the memory device 20. The storage device 20 may be a device fixedly installed in the biometric authentication device 100 or may be a portable device (memory) detachably attached to the biometric authentication device 100. The dictionary DIC is a template file that contains the biometric information DO that is contrasted with the biometric DIN in authentication. As shown in FIG. 1, the storage device 20 has a storage area having a capacity capable of storing a plurality (m in FIG. 1) DIC_1 to DIC_m.

The control unit 30 is a device that controls each unit of the biometric authentication device 100. The control part 30 of this form is a central processing unit (CPU) which functions as the authentication part 32, the pre-management part 34, the pre-reduction part 36, and the auxiliary authentication part 38 by execution of a program. Alternatively, the control unit 30 may employ a hardware circuit such as a DSP including an electronic circuit that realizes the functions of the above units.

The authenticator 32 determines the validity of the subject by matching the biometric information DIN supplied from the information acquisition unit 10 (analysis unit 14) with the biometric information DO of the dictionary DIC stored in the storage device 20. do. The result of the determination by the authentication unit 32 is output to the output unit 50. The dictionary manager 34 executes the update of each dictionary DIC stored in the storage device 20 or the addition of a new dictionary DIC to the storage device 20. The dictionary reduction unit 36 reduces the total number m of dictionary DICs stored in the storage device 20 by merging a plurality of dictionary DICs or deleting one dictionary DIC. The content of the specific process by the prior management part 34 and the prior reduction part 36, and the time of each process are mentioned later. The subsidiary authentication unit 38 is a means for subsidiaryly authenticating the legitimacy of the subject (hereinafter referred to as "secondary authentication") independent of the authentication by the authenticating unit 32.

The operation unit 40 includes a plurality of operator elements operated by the user. The user can instruct the control part 30 to change various variables used for authentication, and to start authentication by operating the operation part 40 suitably. The output part 50 is a means which outputs the result of the authentication by the authentication part 32. As shown in FIG. For example, a display device that outputs the result of authentication as an image and a speaker that outputs the result of authentication by voice are preferably employed as the output unit 50.

<B: Operation of Biometric Authentication Device>

Next, the operation of the biometric authentication device 100 described above will be described with reference to FIGS. 2 to 4.

First, an operation for newly registering a valid user's dictionary DIC_1 (hereinafter referred to as "initial registration") will be described. The user speaks a specific word to the input unit 12 after instructing the apparatus 100 to start initial registration by the operation of the operation unit 40. The analysis unit 14 extracts the section actually spoken by the user from the voice input to the input unit 12 and generates biometric information DO (for example, a vector sequence of cepstrum) by analyzing the waveform in the section. do. Various well-known techniques are employ | adopted for generation of the biological information DO. As shown by a broken line in FIG. 1, the biometric information DO generated by the analysis unit 14 is stored in the storage device 20 as the first dictionary DIC_1.

After the initial registration of the DIC_1 in advance is completed in the above procedure, the controller 30 executes the process of FIG. 2 every time a time is required for authentication. Examples of times when authentication is required include, for example, when an electronic device equipped with the biometric authentication device 100 starts operation based on the input of power, or when the electronic device has a predetermined operation (for example, for specific information). Access). When the authentication starts, the subject then speaks a predetermined word to the input unit 12. The analyzing unit 14 generates the biometric information DIN from the voice and outputs it to the control unit 30 by the same processing as in the initial registration.

When the process of FIG. 2 starts, the authentication part 32 calculates the distance DST_1 of the biometric information DIN acquired from the analysis part 14, and the biometric information DO of the dictionary DIC_1 memorize | stored in the memory | storage device 20 (step SA10). . The distance DST_i (i is an integer that satisfies 1 ≦ i ≦ m) is an index value at which the biometric DIN and the biometric information DO of the dictionary DIC_i are similar (matched). In the calculation of the distance DST_i, various pattern matching techniques such as DP matching for calculating normalized distances between two types of vector sequences are used. The smaller the distance DST_i, the more similar the biometric information DIN of the biometric DIN and the dictionary DIC_i (i.e. the subject is likely to be a legitimate user).

Next, the authenticator 32 determines whether or not the distance DST_1 calculated in step SA10 falls below the threshold value VTHR1 (step SA11). Threshold VTHR1 is a variable stored in the memory | storage device 20, and the control part 30 can be changed suitably according to the operation with respect to the operation part 40. FIG. It should be noted that the threshold value VTHR1 is set to a value that is small enough for the authentication to be sufficiently high accuracy (that is, a value within a range where the similarity is sufficiently high among the ranges of values that can take the distance DST_1). In this regard, when the distance DST_1 is lower than the threshold VTHR1 (that is, when the biometric DIN and the biometric information DO are sufficiently similar), the control unit 30 executes the processing of Step SA12 and Step SA13, and then the subject authenticates the user. The authenticated person is notified through the output unit 50 that the user is authenticated as a legitimate user (step SA14). When the authentication is properly completed as described above, various processes by the electronic device are permitted.

In step SA12, the control unit 30 updates the dictionary DIC_1 of the storage device 20 based on the biometric information DIN newly obtained at the time of authentication (step SA12). For example, the control unit 30 stores the average value of the biometric information DO of the existing dictionary DIC_1 and the new biometric information DIN as the new biometric information DO of the dictionary DIC_1 in the storage device 20. Alternatively, in step SA12, the biometric information DO stored in the storage device 20 may be replaced with a new biometric information DIN.

In following step SA13, the control part 30 reflects the update of this prior DIC_1 to each variable stored in the memory | storage device 20. FIG. In more detail, the control part 30 adds "1" to each of the variable nUPDATE_1 and the variable nUPDATE_all, and initializes the variable nUnUPDATE_1 to zero. The variable nUPDATE_i is the number of times the dictionary DIC_i has been updated in the past. The variable nUPDATE_all is the sum of the number of updates for all the dictionary DICs stored in the storage device 20. The variable nUnUPDATE_i is the number of times of non-update of the dictionary DIC_i indicating the number of times the dictionary DIC_i was not updated at the time of authentication.

When it is determined in step SA11 that the distance DST_1 does not fall below the threshold VTHR1, the control unit 30 determines whether the distance DST_1 falls below the threshold VTHR2 (step SA15). Threshold VTHR2 is a variable stored in the memory | storage device 20, and the control part 30 changes according to the operation with respect to the operation part 40. FIG. It should be noted that the threshold VTHR2 is set to a larger value than the threshold VTHR1 (a value corresponding to the distance DST_1 indicating a similarity lower than the threshold VTHR1).

If the distance DST_1 is within the range between the threshold VTHR1 and the threshold VTHR2, the biometric DIN and the biometric DO are similar to the extent that the subject can be immediately immediately legitimate compared to the case where the distance DST_1 is below the threshold VTHR1. However, the biological information DIN and the biological information DO are not separated from each other so that the validity of the subject can be definitely denied. For this reason, when the distance DST_1 is smaller than the threshold value VTHR2 (VTHR1 ≦ DST_1 <VTHR2), the validity of the subject is determined in consideration of the result of the auxiliary authentication by the auxiliary authentication unit 38 (Step SA16 and Step SA17). ).

In the storage device 20, a password registered in advance by a legitimate user is stored. The auxiliary authentication unit 38 prompts the subject to enter a password (step SA16), and in response, whether the password inputted from the operation unit 40 by the subject and the password registered in the storage device 20 correspond. It is determined whether or not (step SA17). If the determination of step SA17 is affirmed, the control part 30 transfers a process to step SA14 after performing the process of step SA18 and step SA19. That is, after the notification from the output unit 50 that the authentication is properly completed, various processes by the electronic device are possible.

The fact that the distance DST_1 is greater than or equal to the threshold value VTHR1 but is determined to be a legitimate user by auxiliary authentication is most likely a case where the characteristics of the legitimate user's voice vary depending on the legitimate user's physical condition and the surrounding environment. In this regard, when the biometric information DIN having the same characteristics as at this time is input for future authentication, it can be determined immediately as a legitimate user (that is, without even performing secondary authentication by the auxiliary authentication unit 38). In step SA18, the dictionary management unit 34 generates a new dictionary DIC_2 including the biometric information DIN acquired at the time of authentication at this time, and stores it in the storage device 20. The control unit 30 also reflects the addition of the current dictionary DIC_2 to each variable stored in the storage device 20 (step SA19). That is, the control part 30 adds "1" to each of the variable nUPDATE_2 (the number of updates of the dictionary DIC_2) and the variable nUPDATE_all, and initializes the variable nUnUPDATE_2 which is the number of times of the non-update of the prior DIC_2 to zero. Moreover, the control part 30 adds "1" to the variable nUnUPDATE_1 of the dictionary DIC_1 which was not updated by this authentication.

If the distance DST_1 exceeds the threshold VTHR2, the biometric DIN and the biometric DO do not match (step SA15; no), or if the password does not match in the secondary authentication (step SA17; no), the subject is not a legitimate user. Most likely. In connection with this, when the determination of step SA15 or step SA17 is denied, the controller 30 notifies the output unit 50 that the validity of the subject is denied (step SA20). If the validity of the subject is denied as described above, various processing by the electronic device is prohibited.

When a plurality of dictionaries DIC_1 to DIC_m are stored in the storage device 20 by the processing of FIG. 2, the controller 30 performs authentication in the procedure illustrated in FIG. 3 every time a time is required for authentication thereafter. . When the authentication starts, the subject then speaks a predetermined word to the input unit 12. The analyzer 14 generates the biometric information DIN from the voice of the subject and outputs it to the controller 30.

When the processing of FIG. 3 starts, the authentication part 32 is based on the biometric information DO of each of m dictionary DIC_1-DIC_m memorize | stored in the memory | storage device 20, and the distance DST_1 based on the biometric information DIN acquired by the analysis part 14. FIG. DST_m is calculated and the minimum value (hereinafter, referred to as "minimum distance") of the distances DST_1 to DST_m is specified (step SB10). In other words, the minimum distance MINDST is the distance between the biometric information DO and the biometric information DIN having the maximum similarity in the biometric information DIN among the m types of biometric information DOs included in DIC_1 to DIC_m.

Next, the authentication part 32 determines whether the minimum distance MINDST is less than the threshold value VTHR1 (step SB11). If the biometric information DIN and the biometric information DO are similar as the minimum distance MINDST falls below the threshold value VTHR1, the subject can be recognized as a legitimate user. In this connection, when the determination of step SB11 is affirmed, after executing step SB12 and step SB13, the control part 30 notifies the to-be-tested person from the output part 50 that the validity was authenticated (step SB14). If the justification is confirmed as described above, various types of processing by the electronic device are permitted.

In step SB12, the preliminary management part 34 updates the dictionary DIC_dMINDST with the content according to the biometric information DIN by the same process as step SA12 of FIG. The dictionary DIC_dMINDST is a dictionary DIC including the biometric information DO whose distance of the biometric information DIN is the minimum distance MINDST. Moreover, the control part 30 reflects the update of step SB12 to each variable stored in the memory | storage device 20 (step SB13). That is, the control unit 30 adds "1" to each of the variable nUPDATE_dMINDST (the number of updates of the pre-DIC_dMINDST) and the variable nUPDATE_all, and initializes the variable nUnUPDATE_dMINDST (the number of non-updates of the pre-DIC_dMINDST) to zero. In addition, the control unit 30 adds "1" to variables nUnUPDATE_1 to nUnUPDATE_m (except nUnUPDATE_dMINDST) indicating the number of times of non-update for each dictionary DIC other than the dictionary DIC_dMINDST.

If it is determined in step SB11 that the minimum distance MINDST is greater than or equal to the threshold value VTHR1, the control unit 30 determines whether or not the minimum distance MINDST is less than the threshold value VTHR2 as in step SA15 of FIG. 2 (step SB15). When the determination of step SB15 is affirmed, control unit 30 determines whether the total number m of dictionary DICs stored in storage device 20 exceeds the maximum value nMAXDIC (step SB16). The maximum value nMAXDIC is stored in the storage device 20 and changed by the control unit 30 in accordance with an operation on the operation unit 40. If it is determined in step SB16 that the dictionary number m is less than the maximum value nMAXDIC, the subsidiary authentication by the subsidiary authentication unit 38 is performed similarly to step SA16 and step SA17 of FIG. 2 (steps SB17 and SB18). If it is determined in step SB18 that the user is a legitimate user, the advance management unit 34 generates a new dictionary DIC_m + 1 based on the biometric information DIN acquired at the time of this authentication (step SB19). The control unit 30 also reflects the creation of the DIC_m + 1 beforehand in each variable stored in the storage device 20 by the same process as in step SA19 of FIG. 2 (step SB20).

When it is determined in step SB15 that the minimum distance MINDST is equal to or greater than the threshold VTHR2 or when it is determined in step SB18 that the user is not a legitimate user, as in FIG. 2, the controller 30 outputs that the validity of the subject is denied. After notifying (step SB21), various processes by the electronic device are prohibited.

In the case where it is determined in step SB16 that the total number m of dictionary DICs reaches the maximum value nMAXDIC (m≥nMAXDIC), the control unit 30 stores the existing dictionary DICs stored in the storage device 20, as shown in FIG. The process of reducing the number of times is executed. By reducing the dictionary DIC described below, it is possible to add a new dictionary DIC within the range not exceeding the maximum value nMAXDIC in step SB19 of FIG.

When the process of FIG. 4 starts, the control part 30 determines whether the variable nUPDATE_all exceeds the threshold value nCHKDIC (step SC10). If the determination of step SC10 is denied, the control unit 30 proceeds to step SB21 of FIG. 2, and if the determination of step SC10 is affirmed, the control proceeds to step SC11. That is, the process for reducing the existing dictionary DIC is executed on the occasion that the sum of the number of updates (nUPDATE_all) for all the dictionary DIC_1 to DIC_m exceeds the threshold value nCHKDIC. In the threshold value nCHKDIC stored in the memory device 20, the control unit 30 can be appropriately changed in accordance with an operation on the operation unit 40.

In step SC11, the control unit 30 determines whether there is a numerical value exceeding the threshold UnUPDATE_thr in m variables nUnUPDATE_1 to nUnUPDATE_m corresponding to each prior DIC (step SC11). Since the variable nUnUPDATE_i increases when the dictionary DIC_i is not used for authentication in step SA11 or step SB11 (not updated in step SA12 or step SB12), a large variable nUnUPDATE_i means that the use of the dictionary DIC_i is less frequent. (That is, the frequency of obtaining biometric DIN similar to the biometric DO of dictionary DIC_i from the subject is low). In this regard, if the determination of step SC11 is affirmed, the dictionary reduction unit 36 deletes one dictionary DIC whose variable nUnUPDATE_i exceeds the threshold UnUPDATE_thr from the storage device 20, and the number i of each dictionary DIC is added. The remaining (m-1) prior DICs are rearranged so as to continue from "1" to "m-1" (step SC12). Then, after the controller 30 initializes the variables nUPDATE_nMAXDIC and the variable nUnUPDATE_nMAXDIC of the dictionary DIC_nMAXDIC (not created at this point) to be stored in the storage area secured by the deletion in step SC12 (step SC13), FIG. 3. The process proceeds to step SB17 in.

When the determination of step SC11 is negative, the control unit 30 determines whether the variable nMINUPDATE is lower than the threshold UPDATE_thr (step SC14). The variable nMINUPDATE is the minimum value of m variables nUPDATE_1 to nUPDATE_m corresponding to each dictionary DIC. The threshold UPDATE_thr is changed in accordance with an operation on the operation unit 40. Since the variable nUPDATE_i increases each time the dictionary DIC_i is used for authentication in step SA11 or step SB11, a small variable nUPDATE_i means that the frequency of use of the dictionary DIC_i is low. In this connection, if the determination of step SC14 is affirmed, the dictionary reduction unit 36 deletes one dictionary DIC_dMINUPDATE whose variable nUPDATE_i was the minimum value nMINUPDATE from the storage device 20, and the number i of each dictionary DIC is "1". The remaining (m-1) prior DICs are rearranged so as to continue from &quot; m-1 &quot; (step SC15). The control unit 30 then proceeds to step SB17 in FIG. 3 after updating the variable in step SC13.

When the determination of step SC14 is denied, a process (steps SC16 to SC18) for merging two dictionary DICs having similar biometric information DOs among the m dictionaries DIC_1 to DIC_m stored in the storage device 20 is executed. In step SC16, the control unit 30 calculates the distance between the respective DICs for all combinations of selecting two from the m dictionaries DIC_1 to DIC_m stored in the storage device 20, Specifies the minimum value MIN_INTERDIC_DST. Moreover, the control part 30 determines whether the minimum value MIN_INTERDIC_DST is less than the threshold value INTERDIC_thr (step SC17). The threshold value INTERDIC_thr is stored in the storage device 20 and is changed in accordance with an operation on the operation unit 40.

If the determination of step SC17 is denied, the control unit 30 proceeds to step SB21 of FIG. 3, and if the determination of step SC17 is affirmed, the control proceeds to step SC18. In step SC18, the preliminary reduction unit 36 merges two dictionary DICs (that is, two dictionary DICs of the most similar combination of biometric information DOs) having mutual distances of the minimum value MIN_INTERDIC_DST, and the number i of each dictionary DIC is &quot; The remaining (m-1) pre-DICs are rearranged so as to continue from "1" to "m-1" (step SC18). The merging of two dictionary DICs is, for example, a process of newly creating one dictionary DIC including an average value of each bioinformation DO and deleting two existing dictionary DICs. At most, in step SC18, one of the two dictionary DICs whose respective distances are calculated by the minimum value MIN_INTERDIC_DST may be simply deleted. When step SC18 is executed, the control part 30 transfers a process to step SB17 of FIG. 3 after updating a variable in step SC13.

As described above, in this embodiment, when the distance between the biometric information DIN and the biometric information DO (DST_1 in FIG. 2 or MINDST in FIG. 3) is within the range between the threshold value VTHR1 and the threshold value VTHR2, the biometric information DIN is used. A new dictionary DIC is created. For example, a separate dictionary DIC is created for the bioinformation DIN at each immediately after wake up and during daylight activity. In addition, a separate dictionary DIC is created for the bioinformation DIN in each of the static environment and the noisy environment. Therefore, even if the biological information DIN acquired from the legitimate user fluctuates in the short term, it is possible to maintain the accuracy of authentication to a high level.

Further, if the distance exceeds the threshold VTHR2, the validity of the subject is denied, and if the distance is between the threshold VTHR1 and the threshold VTHR2, the auxiliary authentication unit 38 is authenticated auxiliaryly. Therefore, even if the bioinformation DIN and the bioinformation information DO differ to such an extent that each distance exceeds the threshold VTHR1, even if a new dictionary DIC is created, the bioinformation DIN acquired from a valid person other than a legitimate user is based on the bioinformation DIN. The risk of creating a new dictionary DIC is effectively excluded.

Further, when the distance between the biometric information DIN and the biometric information DO of the dictionary DIC_i is less than the threshold value VTHR1, the dictionary DIC_i is updated (step SA12 in FIG. 2 or step SB12 in FIG. 3). Therefore, even in the case where the distance between the biometric DIN and the biometric DO falls below the threshold VTHR1, even when the biometric DIN of the legitimate user changes gradually over a long period of time, the biometric information is maintained at a high level. It is possible to respond to variations in DIN. In addition, the threshold value VTHR1 and the threshold value VTHR2 serving as criteria for determining the validity of the subject are also used as criteria for determining whether to update or add additional DIC. Therefore, the threshold value VTHR1 and the threshold value VTHR2 also have the advantage that the load of the processing by the controller 30 is reduced compared with the configuration in which the update or addition of the pre-DIC is determined based on a separate variable.

By the way, as a method of creating a plurality of dictionaries used for authentication, for example, a plurality of dictionaries are created with respect to the biometric information DO obtained from each meeting utterance by uttering the user several times while changing the utterance method. I think how. However, in this method, there is a problem in convenience because it results in forcing the user to perform a complicated task of talking while changing the method of speaking. In contrast, in this embodiment, the DIC is automatically updated or created in accordance with the distance between the biometric information DIN and the biometric information DO, and the magnitude of the threshold value VTHR1 and the threshold value VTHR2. Therefore, there is an advantage that the accuracy of authentication can be improved at any time without making the user aware of the update or creation of the prior DIC.

Moreover, even if a user is going to change the method of utterance, the actual utterance does not change as much as the difference between the utterance of voice immediately after the weather and in the daytime activity, or the difference of utterance in a static environment and a noisy environment. For this reason, in the method of forcibly changing the vocalization method, it is difficult to carry out high-accuracy authentication until the bioinformation DIN changes significantly in the short term (for example, in the early morning and in the afternoon). According to this form, these problems are also solved.

In this embodiment, the user can appropriately change various variables used for updating, adding, or deleting an authentication or prior DIC. Therefore, it is possible to realize authentication in accordance with the user's request. For example, as the threshold VTHR1 or the threshold VTHR2 is increased, the update or addition of the pre-DIC is performed at a higher frequency. As the threshold VTHR1 or the threshold VTHR2 is decreased, a higher accuracy of authentication is realized. In addition, when the maximum value nMAXDIC of the number of prior DICs is increased, a large number of dictionary DICs are stored in the storage device 20, so that it is possible to cope with various utterances, and when the maximum value nMAXDIC is reduced, the storage device ( The capacity of the data stored in 20) is reduced.

<C: Modification>

Various modifications can be made to each of the above forms. The specific example of a modification is as follows. In addition, you may combine each of the following aspects suitably.

(1) Modification Example 1

In the above embodiment, the configuration in which authentication is performed based on the biometric information DIN extracted from the voice is illustrated, but the biometric information used for authentication is appropriately changed. For example, various characteristic quantities such as vein patterns, facial images, fingerprints, irises, and handwriting in various parts of the body such as the hand and the retina can be used for authentication as biometric DIN. In the case of using the above-mentioned biometric information DIN, a device for recognizing images of each part of the body and the handwriting is employed as the input unit 12. In addition to the voices exemplified in the above embodiments, since the biological information DIN such as the handwriting and the facial form often varies greatly in a short period of time, the present invention in which high-precision authentication is realized regardless of fluctuations in the biological information, these biological information It is particularly preferably employed in the biometric authentication device 100 using DIN for authentication.

(2) Modification 2

In the above aspect, although the structure which the auxiliary authentication part 38 performs auxiliary authentication based on the password input from the operation part 40 was illustrated, the method of auxiliary authentication is changed suitably. For example, instead of the structure which uses the password input from the operation part 40 for authentication, or with this structure, the structure which uses the password input as voice from the input part 12 for authentication is also employ | adopted. That is, the auxiliary authentication unit 38 performs authentication by specifying a password input as voice to the input unit 12 by voice recognition technology and matching this specific password with the password registered in the storage device 20. As can be understood from the above example, the auxiliary authentication unit 38 is based on information (password) acquired from the subject separately from the biometric information DIN, separately from the authentication by the authentication unit 32 (more specifically. In this case, any means may be used for performing auxiliary authentication.

(3) Modification 3

In the above embodiment, the configuration in which the dictionary DICs are reduced one by one is exemplified, but a configuration in which a plurality of dictionary DICs are collectively deleted is also employed. For example, in step SC12 of FIG. 4, the plurality of dictionary DICs in which the variable nUnUPDATE_i exceeds the threshold UnUPDATE_thr may be deleted.

(4) Modification 4

The input unit 12 and the analysis unit 14 may be omitted from the biometric authentication device 100 as appropriate. For example, a configuration in which a terminal including the input unit 12 and the analysis unit 14 is connected to the biometric authentication device 100 via a communication network is also adopted. In this configuration, the biometric information DIN generated by the analysis unit 14 of the terminal is used for authentication after the biometric authentication device 100 receives it via the communication network. In the above configuration, the means for receiving the biometric information DIN from the communication network functions as the information acquisition means in one embodiment of the present invention.

(5) Modification 5

In the above embodiment, the configuration in which the distance DST_i between the biometric information DIN and the biometric information DO is used for authentication is exemplified. However, the numerical value used as an index of the similarity between the biometric information DIN and the biometric information DO is not limited to the distance. For example, a configuration in which authentication is performed based on a variable (indicator value) of a property whose numerical value increases as the biometric information DIN and the biometric information DO are similar is also employed. In the above configuration, the threshold value VTHR2 is smaller than the threshold value VTHR1 (that is, dissimilarity value). In step SA11 or step SB11, it is determined whether or not the indicator value exceeds the threshold value VTHR1 (whether or not the indicator value indicates similarity). In step SA15 or step SB15, whether or not the indicator value exceeds the threshold value VTHR2. Is determined.

(6) Modification 6

Each variable (for example, the threshold value VTHR1 or VTHR2) used for the processing by the control unit 30 may be configured to be individually stored in the storage device 20 for each of a plurality of users. The control unit 30 executes various processes such as authentication, updating, adding or reducing the pre-DIC based on the variable group designated by the subject prior to the authentication among the plurality of variable groups. According to the above structure, when one electronic device is shared by a plurality of users, each user can be appropriately authenticated, and there is an advantage that the convenience of the electronic device is improved.

1 is a block diagram showing a configuration of a biometric authentication device according to an embodiment of the present invention.

2 is a flowchart for explaining the flow of biometric authentication processing by the control unit.

3 is a flowchart for explaining the flow of biometric authentication processing by the control unit;

4 is a flowchart for explaining the flow of biometric authentication processing by the control unit.

<Explanation of symbols for main parts of the drawings>

100: biometric authentication device

10: information acquisition unit

12: input unit

14: analysis unit

20: storage device

30: control unit

32: authentication unit

34: pre-management

36: pre-cutting

38: secondary authentication unit

40: control panel

50: output unit

Claims (10)

As a biometric authentication device, Storage means for storing a dictionary containing biometric information of a registered person; Information acquisition means for acquiring biometric information of the subject, Authentication means for authenticating the validity of the subject, based on an index value indicating the similarity between the biometric information previously stored by the storage means and the biometric information acquired by the information acquisition means; In the first case where the index value indicates a similarity higher than the first threshold value, the dictionary of the storage means is updated based on the biometric information acquired by the information obtaining means, and the index value is lower than the first threshold value. A dictionary for generating a new dictionary according to the biometric information acquired by the information acquiring means and storing the new dictionary generated in the storage means in a second case showing a similarity higher than the second threshold value set lower than the first threshold value; Means of management Biometric authentication device comprising a. The method of claim 1, And the authentication means affirms the validity of the subject in the first case and negates the validity of the subject in the third case where the index value indicates a similarity lower than the second threshold. The method according to claim 1 or 2, Further comprising auxiliary authentication means for authenticating the validity of the subject, separately from the authentication means, In the second case, the prior management means creates the new dictionary when the auxiliary authentication means affirms the validity of the subject, and when the auxiliary authentication means denies the validity of the subject, the new dictionary. Biometric authentication device that does not create a dictionary. As a biometric authentication device, Storage means for storing a plurality of dictionaries each containing biometric information of a registered person; Information acquisition means for acquiring biometric information of the subject, Each of the plurality of dictionaries stored by the storage means indicates similarity between the biometric information and the biometric information acquired by the information acquisition means, and authenticates the validity of the subject based on a plurality of index values corresponding to the plurality of dictionaries. Authentication means, The information acquiring means includes a dictionary corresponding to the maximum index value among the plurality of dictionaries in the storage means in a first case in which the index value at which the similarity degree among the plurality of index values is the maximum is higher than the first threshold value. The information acquiring means is updated on the basis of the acquired biometric information, and in the second case in which the maximum index value is lower than the first threshold but exhibits a similarity higher than the second threshold set lower than the first threshold. Dictionary management means operable to generate a new dictionary according to the acquired biometric information and store the new dictionary generated in the storage means Biometric authentication device comprising a. The method of claim 4, wherein The dictionary management means counts the number of times of updates for each dictionary updated by the dictionary management means among a plurality of dictionaries stored by the storage means, and the device is a dictionary in which the counted number of updates falls below a threshold. And a pre-cutting means for deleting from the storage means. The method of claim 4, wherein The dictionary management means counts the number of non-updates for each dictionary not updated while another dictionary is updated by the dictionary management means, among the plurality of dictionaries stored by the storage means, and the apparatus counts the counted non-updates. And a dictionary reduction means for deleting from the storage means a dictionary whose number of times exceeds a threshold. The method of claim 4, wherein The dictionary management means evaluates the similarity between a plurality of dictionaries stored by the storage means, and the apparatus reduces a dictionary by dividing two dictionaries whose similarity exceeds a threshold by one of them by merging or deleting one of them. Biometric authentication device further comprising means. The method according to any one of claims 5 to 7, And the preliminary reduction means performs a reduction of the dictionary when the total number of dictionaries stored in the storage means reaches a predetermined value. As a biometric authentication method, Obtaining biometric information of the subject, Authenticating the validity of the subject based on an indicator value indicating the similarity between the registered person's biometric information stored in the storage means and the acquired biometric information of the subject, In a first case where the index value indicates a higher degree of similarity than the first threshold value, the dictionary of the storage means is updated based on the acquired biometric information, and the index value is lower than the first threshold value, but the first threshold value. And a second dictionary having a similarity higher than the second threshold set lower, generating a new dictionary according to the acquired biometric information and storing the new dictionary generated in the storage means. A computer-readable recording medium having recorded thereon a program executable by a computer for use in a computer having a storage means for storing a dictionary containing biometric information of a registered person, The program includes: an information acquisition process of acquiring biometric information of the subject in the computer; An authentication process for authenticating the validity of the subject, based on an index value indicating the similarity between the biometric information of the registered person stored in the dictionary stored in the storage means and the biometric information acquired in the information acquisition process; In a first case where the index value indicates a similarity higher than the first threshold value, the dictionary of the storage means is updated based on the biometric information acquired in the information acquisition process, and the index value is lower than the first threshold value. A dictionary for generating a new dictionary according to the biometric information acquired in the information acquisition process and storing the new dictionary generated in the storage means in the second case showing a similarity higher than the second threshold set lower than the first threshold value Management processing A computer readable recording medium having recorded thereon a program executable by a computer, the program instruction for executing the program.

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